Jane Doe 1 and Jane Doe 2 left the Nexus Recovery Center, a substance abuse treatment facility in Dallas, Texas. The girls were 15 years old and 14 years old. At a gas station, they met an adult male they identified as 'Black,' who offered to take them back to his apartment and provide them with narcotics. Jane Doe 1 told Black that the girls were both 15 years old. The girls stayed at Black's apartment for approximately three days. During that time, Black and another man provided Jane Does 1 and 2 with methamphetamine and crack cocaine, and the girls engaged in sex acts with the two men. While staying at Black's apartment, Jane Does 1 and 2 also met another friend of Black's, later identified as D or 'Cheese.' Black later drove the girls to an abandoned area and sold them to D. D took the girls back to his apartment, where he created a Backpage.com ad inviting anyone to engage in commercial sex with 'Kacy.' Using prepaid cell phones, D arranged for men to come to his apartment to engage in sex acts with the girls in exchange for money. Jane Doe 1 would greet them at the door and lead them to a bedroom where she asks them to choose between herself and Jane Doe 2. Both girls would be naked. Jane Doe 1 would collect the cash and pass it under the bathroom door to D, who would be waiting on the kitchen side. Jane Doe 2 estimates she engaged in sex roughly ten times. Jane Doe 1 testified she engaged in commercial sex acts sixteen times per day. D kept all of the money the girls earned. The girls told D they were only 15 and 14 years old. D continued to have the girls engage in commercial sex acts with men. D raped Jane Doe 1 on multiple occasions and Jane Doe 2 at least once. D and his friends provided Jane Does 1 and 2 with a constant supply of crack cocaine. D became violent when the girls got out of line and didn't do what they were told. remained for two more weeks. D became more violent and controlling and regularly abused Jane Doe 1 and pointed a gun at her. An older prostitute convinced her that leaving D was the safest choice. The woman took Jane Doe 1 to another apartment. D showed up less than a day later with three friends and a gun, which he pointed in Jane Doe 1's face. A man staying at the apartment with Jane Doe 1 and the older prostitute came out with a large gun and forced the men to leave without Jane Doe 1. Jane Doe 1 was recovered by the police roughly one week later. Officers were able to locate several Backpage.com ads posted by D. Records from motels identified by Jane Doe 1 confirmed that D had paid for several rooms during the relevant time frame. A year later, D admitted that he knew the girls, that they had stayed with him for a period of time, that they engaged in prostitution, and that he discovered at some point that they were underage. D claimed that when he found out Jane Does 1 and 2 were only 15 and 14 years old, he had them leave his apartment. D admitted that he had set up the Backpage.com ads. D denied that he facilitated their engagement in commercial sex. D eventually, he admitted that he accepted money from them, though he claimed it was only so that he could feed and house them. Several law enforcement witnesses testified, including Officer Halbert and Special Agent Phillip Campbell, who explained how the hotel, cell phone, Backpage.com ads, and social media records obtained during the investigation corroborated the girls' account of their experience. Both law enforcement officers testified that they believed Keys had a reasonable opportunity to observe the girls and that he caused or compelled them to engage in commercial sex acts. D was found guilty and appealed. D's challenges, in part, the admissibility of law enforcement testimony where Halbert and Campbell improperly opined that D was guilty of the offenses charged.